<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="js/vue.js"></script>
</head>
<body>
    <div id="app">
        <div v-if="isShow"ref="self">
            test
        </div>
        <button @click="isShow=!isShow">更新</button>
    </div>
    <script>
        var vm=new Vue({
        el:'#app',
        data:{
            isShow:false
        },
        beforeUpdate() {
            console.log('更新之前');
            console.log(this.$refs.self);
        },
        updated() {
            console.log('更新之后');
            console.log(this.$refs.self);
        },
        })
    </script>
</body>
</html>